Risk factors associated with postcraniotomy meningitis.

OBJECTIVE

The authors conducted a retrospective cohort study to determine the incidence, bacteriological features, and risk factors for postcraniotomy meningitis.

METHODS

Patients older than 18 years who underwent nonstereotactic craniotomies between January 1996 and March 2000 and who survived for more than 7 days were included. Operations for placement of burr holes and shunts were excluded. Records of the first 30 postoperative days were abstracted. Host factors, types of craniotomy, and pre- and postoperative variables were evaluated as risk factors for meningitis

RESULTS

Among 453 patients, there were 25 cases of meningitis. Eight out of 12 culture-positive cases were the result of gram-positive cocci. Four hundred twenty (92%) patients received antibiotic prophylaxis, most commonly a first-generation cephalosporin. In multivariate analysis, the risk of meningitis was increased by surgery that entered a sinus (odds ratio [OR], 4.49; P = 0.018), an increase in the American Society of Anesthesiologists score (OR, 1.72; P = 0.023), and increases in the number of days of external ventricular drainage (OR, 1.21; P = 0.049) and intracranial pressure monitoring (OR, 1.24; P = 0.002).

CONCLUSION

Access of upper airway bacteria to the surgical wound, host factors as expressed by the American Society of Anesthesiologists score, and duration of device-related postoperative communication of the cerebrospinal fluid and the environment are major risk factors for postoperative meningitis after craniotomy.